Methylome, transcriptome, and phenotype changes induced by temperature conditions experienced during sexual reproduction in Fragaria vesca.

Temperature conditions experienced during embryogenesis and seed development may induce epigenetic changes that increase phenotypic variation in plants. Here we investigate if embryogenesis and seed development at two different temperatures (28 vs. 18°C) result in lasting phenotypic effects and DNA methylation changes in woodland strawberry (Fragaria vesca). Using five European ecotypes from Spain (ES12), Iceland (ICE2), Italy (IT4), and Norway (NOR2 and NOR29), we found statistically significant differences between plants from seeds produced at 18 or 28°C in three of four phenotypic features investigated under common garden conditions. This indicates the establishment of a temperature-induced epigenetic memory-like response during embryogenesis and seed development. The memory effect was significant in two ecotypes: in NOR2 flowering time, number of growth points and petiole length were affected, and in ES12 number of growth points was affected. This indicates that genetic differences between ecotypes in their epigenetic machinery, or other allelic differences, impact this type of plasticity. We observed statistically significant differences between ecotypes in DNA methylation marks in repetitive elements, pseudogenes, and genic elements. Leaf transcriptomes were also affected by embryonic temperature in an ecotype-specific manner. Although we observed significant and lasting phenotypic change in at least some ecotypes, there was considerable variation in DNA methylation between individual plants within each temperature treatment. This within-treatment variability in DNA methylation marks in F. vesca progeny may partly be a result of allelic redistribution from recombination during meiosis and subsequent epigenetic reprogramming during embryogenesis.

Diversity of woodland strawberry inflorescences arises from heterochrony regulated by TERMINAL FLOWER 1 and FLOWERING LOCUS T.

A vast variety of inflorescence architectures have evolved in angiosperms. Here, we analyze the diversity and development of the woodland strawberry (Fragaria vesca) inflorescence. Contrary to historical classifications, we show that it is a closed thyrse: a compound inflorescence with determinate primary monopodial axis and lateral sympodial branches, thus combining features of racemes and cymes. We demonstrate that this architecture is generated by 2 types of inflorescence meristems differing in their geometry. We further show that woodland strawberry homologs of TERMINAL FLOWER 1 (FvTFL1) and FLOWERING LOCUS T (FvFT1) regulate the development of both the racemose and cymose components of the thyrse. Loss of functional FvTFL1 reduces the number of lateral branches of the main axis and iterations in the lateral branches but does not affect their cymose pattern. These changes can be enhanced or compensated by altering FvFT1 expression. We complement our experimental findings with a computational model that captures inflorescence development using a small set of rules. The model highlights the distinct regulation of the fate of the primary and higher-order meristems, and explains the phenotypic diversity among inflorescences in terms of heterochrony resulting from the opposite action of FvTFL1 and FvFT1 within the thyrse framework. Our results represent a detailed analysis of thyrse architecture development at the meristematic and molecular levels.

Two MYB activators of anthocyanin biosynthesis exhibit specialized activities in petiole and fruit of diploid strawberry.

The R2R3-MYB transcription factor FveMYB10 is a major regulator of anthocyanin pigmentation in the red fruits of strawberry. fvemyb10 loss-of-function mutants form yellow fruits but still accumulate purple-colored anthocyanins in the petioles, suggesting that anthocyanin biosynthesis is under distinct regulation in fruits and petioles. From chemical mutagenesis in the diploid wild strawberry Fragaria vesca, we identified a green petioles (gp)-1 mutant that lacks anthocyanins in petioles. Using mapping-by-sequencing and transient functional assays, we confirmed that the causative mutation resides in a FveMYB10-Like (FveMYB10L) gene and that FveMYB10 and FveMYB10L function independently in the fruit and petiole, respectively. In addition to their tissue-specific regulation, FveMYB10 and FveMYB10L respond differently to changes in light quality, produce distinct anthocyanin compositions, and preferentially activate different downstream anthocyanin biosynthesis genes in their respective tissues. This work identifies a new regulator of anthocyanin synthesis and demonstrates that two paralogous MYB genes with specialized functions enable tissue-specific regulation of anthocyanin biosynthesis in fruit and petiole tissues.

A roadmap for research in octoploid strawberry.

The cultivated strawberry (Fragaria × ananassa) is an allo-octoploid species, originating nearly 300 years ago from wild progenitors from the Americas. Since that time the strawberry has become the most widely cultivated fruit crop in the world, universally appealing due to its sensory qualities and health benefits. The recent publication of the first high-quality chromosome-scale octoploid strawberry genome (cv. Camarosa) is enabling rapid advances in genetics, stimulating scientific debate and provoking new research questions. In this forward-looking review we propose avenues of research toward new biological insights and applications to agriculture. Among these are the origins of the genome, characterization of genetic variants, and big data approaches to breeding. Key areas of research in molecular biology will include the control of flowering, fruit development, fruit quality, and plant-pathogen interactions. In order to realize this potential as a global community, investments in genome resources must be continually augmented.

The NSPCC UK Minding the Baby® (MTB) home-visiting programme, supporting young mothers (aged 14-25) in the first 2 years of their baby's life: study protocol for a randomised controlled trial.

BACKGROUND: Young mothers living in low-income urban settings often are exposed to significant and chronic environmental difficulties including poverty, social isolation and poor education and typically also have to cope with personal histories of abuse and depression. Minding the Baby® (MTB) is an interdisciplinary home-visiting programme developed to support first-time young mothers, which integrates primary care and mental health approaches into a single intensive intervention from the last trimester of pregnancy until the child's second birthday. The primary aim of the intervention is to promote caregiver sensitivity, and, secondarily, to promote both child and maternal socioemotional outcomes. METHODS/DESIGN: This is a multisite randomised controlled trial (RCT) with a target recruitment of 200 first-time adolescent mothers (under 26 years of age). One hundred participants will be randomised to the MTB group and they will receive the MTB programme in addition to the usual services available in their areas. Those participants not allocated to MTB will receive Treatment as Usual (TAU) only. Researchers will carry out blind assessments at baseline (before the birth of the baby), and outcome assessments around the child's first and second birthdays. The primary outcome will be the quality of maternal sensitivity and the secondary outcomes will focus on attachment security, child cognitive/language development, behavioural problems, postponed childbearing, maternal mental health and incidents of child protection interventions. DISCUSSION: This study evaluates the Minding the Baby® programme in the UK. In particular, this RCT explores the effectiveness of this integrative approach, which focusses on maternal mental issues as well as parent-infant interaction, parental concerns and developmental outcomes. TRIAL REGISTRATION: ISRCTN08678682 (date of registration 3 April 2014).